1. Field of the Invention
The present invention relates to a wiper device for a vehicle which absorbs an abnormal load applied thereto.
2. Description of the Prior Art
Conventionally, in wiper devices for vehicles, there is a drawback in that when the wiper device is operated with, for example, snow having accumulated on the wiper wiping range, the wiper blades collide against the accumulated snow such that the wiping operation is hampered. Therefore, abnormal load is generated at the wiper blades, and the operation of the entire wiper device stops.
In order to overcome this drawback, Japanese Utility Model No. 5-56694 discloses a wiper device for a vehicle which absorbs abnormal load such that continuous operation is possible.
As illustrated in FIGS. 10 and 11, in this wiper device, a first link rod 113 and a first pivot lever 114 are connected via a segment lever 115. The segment lever 115 is formed by a first connecting portion 121, which is supported so as to rotate freely with the first pivot lever 114, and a second connecting portion 122, which is set apart from the first connecting portion 121. The second connecting portion 122 is fixed by a second connecting pin 114c at whose outer periphery a buffer member 110 is disposed. In accordance with this wiper device, when abnormal load is applied, the segment lever 115 rotates around the first connecting portion 121 a predetermined angle with respect to the first pivot lever 114. The buffer member 110 compressively deforms in the radial direction in accordance with the rotation of the segment lever 115, so that the abnormal load can be absorbed.
However, in this disclosed art, the first pivot lever 114 and the segment lever 115 are attached at the first connecting portion 121 so as to be freely rotatable. A drawback arises in that, because there is joggling between the first connecting portion 121 and the segment lever 115, the dimensions of the first connecting portion 121 and the segment lever 115 must be strictly managed during manufacturing.
The rotational angle of the segment lever 115 is determined by the outer diameter dimension of the buffer member 110. Therefore, a drawback arises in that, in order to handle abnormal loads of wiper devices having large wiping angles, the outer diameter of the buffer member 110 must be made large, which leads to an increase in the size of the wiper device.
Other art related to the present invention are disclosed in U.S. Pat. No. 4,765,018; DE 3734309A1; DE 2820104A1; and FR 2557051.